Happiness Is Contagious; Depression Is Not

Happiness not only spreads, it could actually help prevent depression, according to a new study. (Photo: Lachlan Hardy/Flickr)

Depression is not contagious, according to a new study published in the journal Proceedings of the Royal Society B. Happiness, however, is more likely to spread between friends, and the results from the study may help remove some of the stigma surrounding depression.

The World Health Organization estimates that 350 million people worldwide are currently living with depression. Unfortunately, we haven’t made much progress in lowering that number, even though there are literally entire scientific journals devoted to the subject. Preliminary studies have now shown that social support and friendships may be a major factor in lifting you out of a diagnosed funk. Thanks to a detailed study, we have some of the first empirical evidence that happiness is contagious, and that those who befriend depressed people are not in danger of becoming depressed themselves.

Researchers examined data from over 2,000 teenagers who had reported their network of friendships and answered questions about their levels of happiness as part of an earlier research project. Based on the survey results, the scientists classified each student into either a “low mood” (depressed) category a or “healthy mood” (not depressed) category. Then, they mapped out friendships and ran computer simulations to determine whether happiness and sadness spread between friends like an infectious disease.

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The result? Depression is not contagious. Meanwhile, happiness not only spreads—it may prevent (and even help people recover from) depression. The model suggests that teens with five or more happy friends have half the probability of suffering from depression over a six to 12-month period than teens without no “healthy mood” friends. And adolescents with 10 healthy friends have more than double the probability of recovering from depressive symptoms.

“This was a big effect that we have seen here,” said Thomas House, mathematics professor at the University of Manchester and coauthor on the study in a prepared statement. “It could be that having a stronger social network [the real-life version, not Facebook] is an effective way to treat depression.”

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Since the study suggests teens are not at risk of “catching” depression from their friends, and having happy friends may prevent and even pull teens out of depression, House and his colleagues stress that it is important to promote any friendship between adolescents. Friendship is a win-win, the study says—it can’t hurt, but it may be both protective and curative.

“If we enable friendships to develop among adolescents (for example providing youth clubs) each adolescent is more likely to have enough friends with healthy mood to have a protective effect,” House said in a prepared statement. “This would reduce the prevalence of depression.”

By Joshua A. Krisch, for Vocativ

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